System for filling internally pressurized dispensing container



C. P. CLAPP Dec. 48, 1970 SYSTEM FOR FILLING INTERNALLY PRESSURIZEDDISPENSING CONTAINER Filed June 11. 196s 3 Sheets-Sheet l M5L, da@

ATTORNEYS C. P. CLAPP Dec. 8, 1970 SYSTEM FOR FILLING INTERNALLYPRESSURIZED DISPENSINGnv CONTAINER Filed June ll. 1968 5 Sheets-Sheet lN .G m

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ATTORNEYS C. P. CLAPP Dec. 8, 1970 SYSTEM FOR FILLING INTERNALLYPRESSURIZED DISPENSING CONTAINER Filed June ll, 1968 5 Sheets-Sheet .'5

la sim@ ATTORNEYS United States Patent O 3,545,162 SYSTEM FOR FILLINGINTERNALLY PRESSUR- IZED DISPENSING CONTAINER Clarence P. Clapp,Milford, Conn., assignor to Aerosol Techniques Research Center,Incorporated, Milford, Conn., a corporation of New York Filed June 11,1968, Ser. No. 736,198 Int. Cl. B65b 31 00 U.S. Cl. 53-22 8 ClaimsABSTRACT F THE DISCLOSURE A system for lling aerosol type containers(containers the contents of which are discharged through a valve as aspray or a foam by internal pressure generated by a liquied materialthat is a gas at room temperature and pressure) wherein a verysubstantial amount of the air in the head space of a container is purgedby incorporating a small amount of dichlorodilluoromethane in theconcentrate. The concentrate contains an organic solvent in which thedichlorodiiluoromethane is soluble. The concentrate, including thesolvent and the dichlorodifluoromethane, are introduced into thecontainer while the interior of the container is exposed to theatmosphere. Subsequently the interior of the container is subjected to avacuum equal to or somewhat lower than the vapor pressure of the blendincluding the solvent and the dichlorodiiluoromethane whereby enough ofthe dichlorodiiluoromethane evaporates to displace most of the air inthe container over the concentrate. Thereafter while the interior of thecontainer is still under the aforesaid vacuum a valved cap is sealed tothe container as by crimping. The valved cap is placed on (but notsealed to) the container prior to subjecting the interior of thecontainer to the vacuum but the vacuum must be present prior tointroduction of the propellant gas so that air purging precedespropellant gas introduction. The propellant gas may be introduced eitherunder the valved cap prior to the crimping or through the dispensingtube after crimping of the valved cap to the container.

BACKGROUND OF THE INVENTION Field of the invention A system for fillingaerosol type containers characterized in that purging of air in the headspace is effected by introducing into a solvent-containing-concentrateand/or solvent to be incorporated therein a highly volatile purgingliquid consisting of a predominant amount of dichlorodiuoromethane. Thepurging liquid is introduced into the container while the interior ofthe same is under atmospheric pressure, following which a valved cap isloosely placed over the mouth of the container, the interior of thecontainer is subjected to subatmospheric pressure and the cap is crimpedafter which a conventional gas propellant is introduced through thedispensing tube or the gas propellant is introduced under the cap priorto crimping, but after purging, in which event the vacuum is brokenbefore crimping.

Description of the prior` art Present filling systems used for aerosolcontainers (containers the contents of which are discharged through avalve as a spray or a foam by internal pressure generated by a liquiedmaterial that is a gas at room temperature and pressure) are subject tothe defect that consider- Fice able quantities of air are present in thehead space over the container charge. The air, of course, containsoxygen. The presence of this oxygen is deleterious to the operation ofthe container for various reasons. One is that it tends to corrode theinterior of the container whether the can be unlined or even if thecontainer is lined. In the latter event the corrosion takes placethrough pinholes in the lining.

This corrosion is caused in part by the oxygen of the air in the headspace and is enhanced by the presence of water in the charge. It isextremely difficult to provide a charge which is fully anhydrous. Somewater almost invariably is present in one or more of the constituents ofthe charge which in combination with the air engenders the aforesaidcorrosion.

Another ancillary problem associated with the presence of air in thehead space is that the air provides a par'tial vapor pressure which addsto the total vapor pressure in the container. Under certaincircumstances, particularly in warm temperatures or climates, thisincreased vapor pressure brought about by the presence of the air canraise the total vapor pressure to a value which exceeds acceptablestandards. This is particularly true where the container is made ofglass but also is a valid objection to the presence of massive amountsof air in the head space of a metal container.

Furthermore, there are various constituents which are present in thecharge of the container, such for instance as perfumes and often othercomponents, which are sensitive to oxygen in the head space so that thepresence of air in substantial quantities in the head space tends todeteriorate such oxygen-sensitive materials. This in turn lowers,sometimes by a considerable amount, the shelf life of aerosolcontainers.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a system for filling aerosol type containers which avoids theforegoing drawbacks and specifically which very appreciably reduces theamount of air (and, therefore, oxygen) in the head space.

It is a particular object of the present invention to provide a systemof the character described in which the air in the head space issubstantially purged by dissolving liquid dichlorodiuorornethane or anequivalent highly volatile liquid containing up to of said compound inthe concentrate or solvent that is charged into the container, saidliquid being soluble in said solvent the purging being carried out in aspecially effective fashion by pulling a vacuum inside the containerafter the container has been charged under ambient room pressure butbefore the main body of the propellant has been introduced, such mainbody of the propellant being introduced either under the cap or throughthe dispensing tube of a valved cap that eventually is sealed to thecontainer.

Another object of the invention is to provide a system of the characterdescribed which by minimization of the amount of air in the head space,reduces the tendency to corrosion of metal containers, reduces the vaporpressure present in the head space to more acceptable values and extendsshelf life of aerosol containers charged with constituents including oneor more materials that are sensitive to oxygen in the head space.

Other objects of the invention in part will be obvious and in part willbe pointed out hereinafter.

The invention accordingly consists in the combinations of elements andseries of steps which will be exemplified in the systems hereinafterdescribed and of which the scope of application will be indicated in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings in whichare shown various possible embodiments of the invention,

FIG. 1 is a iiow chart of one aerosol filling system which incorporatesthe invention;

FIG. 2 is a ow chart of another system incorporating the invention; and

FIG. 3 is a ow chart of still a third system incorporating theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general the presentinvention is carried out by introducing a nontoxic, nonflammable, highlyvolatile liquid into the concentrate, including an organic solvent, orby mixing this liquid with the organic solvent itself which subsequentlyis added to the concentrate. The said highly volatile liquid is presentin a rather small amount which will vary between about 0.5% to about5.5% by weight of the total amount of the organic solvent, that is tosay, the amount of organic solvent totally present in the concentrate orin the superconcentrate plus the balance of the organic solvent whichsubsequently may be added. This highly volatile liquid must have a lowboiling point which is between about minus 10 F. to about minus 45 F. inorder to avoid insufficient vapor pressure and any tendency to superheatwhich would in consequence hold the highly volatile liquid too tightlyto flash off at a subsequent step in the process in which it displacesthe air, i.e., purges the air in the head space prior to introduction ofthe main body of the propellant gas. The aforesaid highly volatileliquid principally constitutes a substance known as Freon 12 and also asP-12 this being dichlorodiuoromethane. The aforesaid highly volatileliquid necessarily includes at least 90% P-12 by weight and mayconstitute any fraction thereof from 90% to 100%. The highly volatileliquid may include also other highly volatile liquids such for instanceas liquid Freon 114, which is dichlorotetrauoroethane, liquid Freon 22which is difluoromonochloromethane, liquid n-butane, liquid isobutaneand liquid propane. As is apparent from the premise just above stated,the additional materials in the highly volatile liquid, that is to say,the materials other than dichlorodifluoromethane, should not, in toto,exceed about 10% and may range down to 0%. Furthermore, the highlyvolatile liquid, which either constitutes all dichlorodifluoromethaneand in any event not less than 90% thereof, and which is characterizedby its stability, nontoxicity and nonammability, despite the presence ofminor amounts of liquied gases which may, per se, be ammable whenvaporized, is soluble in the solvent which is chargedinto the aerosolcontainer either as part of the concentrate or as an additional liquidwhich is added to a superconcentrate, such solvent being organic.Obviously, in the case of the organic solvent being present in theconcentrate, the solvent will contain active ingredients dissolved ordispersed therein, e.g., antiperspirants, cleaners, waxes, oils,solubilizing agents, paints, perfumes, natural and synthetic gums,resins, germicides, water repellants, esters, coloring agents, etc. Theblend of the organic solvent used for the concentrate or added to thesuperconcentrate and the highly volatile liquid predominantly consistingof dichlorodifluoromethane will exert a total vapor pressure which isthe function of the mole fraction of each volatile ingredient times itsvapor pressure divided by the sum of the mole fractions of all thesolvents present.

Examples of the organic solvents, which either constitute a part of theconcentrate as charged into a container or which is added before, duringor after the superconcentrate is charged into a container and whichQlVGnts have had blended therewith the highly volatile liquidpredominantly comprising dichlorodifluoromethane, include such standardorganic solvents as are used widely in the aerosol container field(depending on the desired formulation) and are exemplified by alcoholssuch as ethanol and isopropanol (both essentially anhydrous), aliphaticpetroleum derivatives such as Isopar E, mineral spirits such as ShellsMineral Spirit 150, aromatic petroleum derivatives such as xylene andtoluene, esters such as isopropyl myristate, isopropyl adipate anddiisopropyl palmitate, mineral oils, glycol ethers such as ethyleneglycol nionobutylether, ethylene glycol monoethylether and ethyleneglycol monomethylether, ketones such as acetone, methylethyl ketone,methylisobutyl ketone, chlorinated solvents such as perchloroethylene,1,1,l-trichloroethylene, and turpentine.

It is also proper to mention at this point that dichlorodiuoromethane ispreferred not only for its low-boiling point, nontlammability,nontoxicity and stability but also for its inertness, i.e., lack oftendency to chemically react with other components of the materialswhich are charged into aerosol containers in general, such for instanceas all kinds of active ingredients used for discharge by the aerosolmethod, as Well as the propellants and solvents that are conventionallyemployed in this eld.

The total vapor pressure of the blend of the organic solvent employedand the highly volatile liquid which predominantly consists ofdichlorodiiiuoromethane and which liquid is present in an amount betweenabout 0.5% and about 5.5% by weight of the organic solvent, should,according to the invention, have a vapor pressure of not less than 5p.s.i.a. (20 of mercury vacuum) nor more than about l2 p.s.i.a. (6 ofmercury vacuum).

The new system is sufiiciently flexible so that the highly volatilesolvent can be introduced as noted above either into the concentratewhich will contain the organic solvent or it may be introduced into theorganic solvent which is added to a superconcentrate which may or maynot contain organic solvent, being added before, during or afterintroduction of the superconcentrate into a container.

An aerosol container is lled with the concentrate which includes theorganic liquid, or the superconcentrate and organic solvent, the organicsolvent in either instance having dissolved therein the highly volatileliquid described above, and this filling is performed with the interiorof the aerosol container exposed to atmospheric pressure, the fillingbeing carried out under ambient room temperature conditions such forinstance as temperatures ranging between about 60 F. to about 80 F., theparticular temperature not being critical and any temperature beingacceptable at which personnel can perform efficiently. At this stage theaerosol container is not hermetically closed, although the cap may be inplace but in such case will not be sealed to the container as bycrimping. Moreover, at this stage, as previously mentioned, the highlyvolatile liquid will be present in the amount of about 0.5% to about 5.5by weight of the organic solvent so that the combined vapor pressure ofthe solvent and highly volatile liquid will be between about 5 p.s.i.a.and about l2 p.s.i.a. Still further, at this stage the main body of thepropellant liquiiied gas has not yet been introduced into the container.It has been observed and a somewhat more detailed comment on thisfeature will be made at a subsequent point, that the highly volatileliquid will not evaporate rapidly when mixed in the aforesaidproportions with conventional aerosol organic solvents. Indeed thehighly volatile liquid will only be lost in small amounts from aconcentrate or organic solvent over extended periods of quiescentstanding in an unsealed tank having a lid. For instance if thedichlorodiiiuoromethane is present in an amount of 4% by weight of theorganic solvent and the organic solvent is present either in aconcentrate or by itself and furthermore if the organic solvent with orwithout the remaining ingredients of the concentrate are disposed in anunsealed tank with a lid at room temperature for as long as three (3)days there is only a loss of about 0.5% of the dichlorodifluoromethanewhich percentage is by weight of the solvent so that after this periodof three (3) days, dichlorodifluoromethane still is present, in anamount of about 3.5% by weight of the organic solvent. Hence, after theaerosol containers have been filed to the amount desired -Wtih theconcentrate containing the organic solvent and highly volatile liquid ora superconcentrate plus an organic solvent with the highly volatileliquid, the dwell time during which the fill is exposed to theatmosphere is not of critical importance insofar as loss of thedichlorofluoromethane is concerned except, of course, insofar as thedwell time lowers filling efficiency and ties up equipment and space.

Thereafter, as an important and critical factor of the invention, theinterior of the aerosol container which at this time still does not havetherein the main body of the liquied gas propellant therein, isevacuated to a vacuum of between about 12 p.s.i.a. and 3 p.s.i.a.preferably in a short time. The time is short for various reasons, onebeing a matter of economy in space and the other is the desire not tosubstantially exhaust all of the highly volatile liquid present in thefill. A satisfactory time is about one l (1) second. However, this timecan range from about 1/3 of a second to about 11/2 seconds, satisfactoryresults being obtained throughout the entire range with the betterresults being secured over the longer periods of time of evacuation,bearing in mind that the longer periods of evacuation tend to tie up theequipment too long.

During this evacuation the highly volatile liquid tends to evaporaterapidly and its vapor to move upwardly through the existing head spacein the can in the form of a cloud of vapor which pushes the air ahead ofit and substantially fills the head space above the charge with thevapor of the highly volatile liquid, i.e., the dichlorodifluoromethanewith minor percentages of the other highly volatile liquids. Thedisplacement action of the vapor, moreover, takes place without a markedboiling and splashing of the liquid fill then present in the can so thatthe evacuation is essentially a clean operation not tending todisseminate particles of liquid out over the open top of the containerand to fall on to equipment, personnel and the floor around theevacuation station and moreover not tending to lose the expensive activeingredients of the concentrate. The amount of the highly volatile liquidwhich evaporates during evacuation, although it performs the purging ofthe air with effectiveness as later will be pointed out by figuresgiven, is not a substantial amount. For instance, when the vacuum ispulled for approximately one (1) second, about .3% of the highlyvolatile liquid (on the basis of its relationship to the organicsolvent) is evaporated and in the main passed through the vacuum pump.

The mixture of the concentrate or superconcentrate and the organicsolvent and the highly volatile liquid is filled into anopen-to-the-atmosphere container by means of a conventional concentratefiller of a type well known to the art in varying amounts depending uponthe nature of the particular fill and desire of the trade. Typically,the combined amount of said concentrate with its organic solvent and thehighly volatile liquid is introduced into a container in an amount suchas to leave a head space of at least 1A; but not more than about 4/s ofthe capacity of the container.

Next, a valve is placed over the top of the open con` tainer. The valveis part of a cap for the open mouth of the container. The valve is notsealed, e.g., by crimping, to the container so that the placement of thevalve does not hermetically seal the container which thereby remainsopen to the atmosphere.

Next, pursuant to the invention, the requisite vacuum is pulled whichcauses the purging of most of the air in the head space.

Subsequently, the cap with its valve is crimped to the container tohermetically seal the interior of the container from the atmosphere andthe can is gassed with the main body of propellant liquid, either stepbeing first and the other second.

The vacuum employed is a function of the vapor pressure of the blend ofthe highly volatile liquid and the organic solvent.

The container is gassed in any conventional manner. For instance, it maybe gassed through the dispensing tube with the dispensing valve open. Italso is within the scope of the present invention to gas the containerimmediately prior to sealing and while the container is still in asubatmospheric condition. Such method of gassing is known asunder-the-cap gassing. A liquid gas in such instance is introduced intothe container through the annular crevice which surrounds the juncturebetween the cap and the mouth of the container.

It will be appreciated that the gassing referred to constitutes theintroduction of the main body of a conventional liquied gas propellant.Such gassing is, per se, well known in the art and forms no part of thepresent invention except that its place in the sequence of stepsconstituting the present system is important, that is to say, thegassing must be performed subsequent to evacuating the then existinghead space in the interior of the aerosol container so as to give thehighly volatile liquid time to purge most of the air.

The final head space which is present after gassing and whichconstitutes the space above the concentrate and the blend of organicsolvent and the highly volatile liquid, and the main body of theliquified gas propellant will vary in accordance with manufacturingspecifications. It is usual, and this applies to the present invention,for the final head space to vary between about 10% and about 30%. Lessthan about 10% would not leave sufficient room for thermal expansion andmore than about 30% would be considered uneconomical. As to the amountof gas, i.e., main body of liquid gas propellant, introduced subsequentto evacuation for purging of air, this too will vary widely dependingupon trade usage, manufacturers specifications and state of the art. Aslittle as 3% by weight of liquified gas propellant, up to as much as byweight of liquified gas propellant may be employed, the percentage byweight of the main body of the liquified gas propellant being based uponthe total till of the container which includes not only the main body ofthe liquified gas propellant but also the concentrate, the organicsolvent and the highly volatile liquid.

Further, with respect to the degree of evacuation, i.e., the value ofthe vacuum pulled, it preferably will be n the range of between about 12p.s.i.a. and 2 p.s.i.a. which corresponds to about 6" of mercury toabout 26" of mercury. The vacuum which prevails during the evacuation(air purging) step preceding sealing and preceding the introduction ofthe main body of the liquified gas propellant should be in a rangebetween the vapor pressure of the blend of the organic solvent and thehighly volatile liquid and a lower value which is not more than about 3p.s.i.a. below said Vapor pressure of the blend. Thus, by way ofexample, a blend of organic solvent and highly volatile liquid having avapor pressure of 5 p.s.i.a. should be evacuated prior to crimping(sealing) and gassing under a vacuum of between 5 p.s.i.a. and 2p.s.i.a. On the other hand a blend of organic solvent and highlyvolatile liquid having a vapor pressure of 12 p.s.i.a. should beevacuated prior to crimping (sealing) and gassing at a vacuum of between12 p.s.i.a. and 9 p.s.i.a.

Of course, the vacuum pulled is maintained during crimping if this isfirst performed Iand also will be maintained during the start ofpropellant filling if under-thecap propellant filling is first employed.

The organic solvent/highly -volatile liquid of the concentrate to headspace volume must be between about 'Ms to about Ms at one end of therange to about 1 to about 4 at the other end of the range. In the firstinstance Iwhich is about 'Vs to 1A, the minimum head space thus providedis needed to supply room for the main body of the liquified gaspropellant and for thermal expansion of the liquid contents of theaerosol container. At the other end of the range, which is about l toabout 4 Athe maximum head space ensuing is to insure a supply of highlyvolatile liquid/organic solvent to purge the head space duringevacuation.

One might expect, as has been mentioned above, that retention of thehighly volatile liquid in the organic solvent and/or the concentratecontaining organic solvent, where such a highly volatile liquid asdescribed is employed, would result in high losses of the highlyvolatile liquid during handling and filling and evacuation (for airpurging) and would cause foaming, bubbling and inability to control thecomposition and weights in the filling and evacuation equipment.Concentrations higher than about 5.5% by weight of the highly volatileliquid in the organic solvent or carrier containing the organic solventcannot be handled pursuant to the present invention at ambient.temperatures and this, therefore, constitutes the higher end of therange of said highly volatile liquid heretofore mentioned. Greateramounts than said 5.5% by weight of the highly volatile liquid wouldrender it impossible to fill controlled formulations under massproduction conditions into aerosol containers. The present inventor hastested mixtures in the indicated range of between about 0.5% and about5.5% by weight of the highly volatile liquid to the organic solventunder both laboratory and high speed production conditions and has foundthat these mixtures do not boil, foam or change in compositionsufficiently to noticeably affect utility under the severe handlingexperienced due to agitation encountered l in pumps, filters, fillers,etc., providing that the Vapor pressure of the blend of highly volatileliquid in the organic solvent is in the indicated range of about 5p.;.i.a. to about l2 p.s.i.a. and the vacuum pulled for purging iswithin the indicated limits. Under these parameters the charge can behandled during filling and appropriate evacuation can be effectedwithout deleterious effects and while insuring that a sufiicientquantity of the highly volatile liquid vapors rises from the organicsolvent to displace substantially all the air in the head space of thecontainer whereby air removal is greatly improved and the process iscontrollable with predictable compositions and results. Essentially, thecompositions are controlled because of a predictable, repeatable andconsistent change in the composition under the aforesaid controlledconditions which causes only a slight loss of the highly volatile liquidduring evacuation. Actually, about 5% to of the highly volatile liquid,based on the original amount of the highly volatile liquid present anddissolved in the organic solvent, is removed from the organicsolvent/highly volatile liquid blend during the purging of air from thehead space of the container. lf all conditions are held substantiallyconstant, the amount of the highly volatile liquid lost duringevacuation is highly consistent, yielding highly uniform compositionsresulting in very uniform vapor pressures in the head space, resultingin highly uniform displacement of air and elimination of most of theundesirable oxygen that would be present if any other methods werefollowed.

"lt is also interesting to observe that the ratio of the highly volatileliquid to the organic solvent does not change in compositionsignificantly during routine storage preceding filling where the produceis not agitated and, therefore, this combination of the organic solventand the highly volatile liquid can be held in nonpressurized vessels forprolonged periods of time without significant changes in composition.This is very desirable in manufacturing procedures inasmuch as itpermits large amounts of the blends of organic solvent and highlyvolatile liquid to be prepared in advance.

It is possible to dissolve the highly volatile liquid in the organicsolvent by straightforward injection with stirring since the equilibriumof the highly volatile liquid organic solvent mixture favorssolubilization of dichlorodifiuoromethane up to the upper limitindicated, to wit, 5.5 by Weight of the Solvent. It should also bementioned that the highly volatile liquid can be incorporated in theorganic solvent in Ivarious other manners, a typical mode being spargingwhich constitutes introduction of a small stream of the highly volatileliquid into a body of a larger stream of the organic solvent either byitself or as part of the concentrate.

Set forth below are several examples of the various compounds and stepsemployed in different systems following the present invention:

EXAMPLE I Aerosol antiperspirant.-The first step is to fill an openaerosol container with a concentrate composed of the following:

Percent by weight Aluminum chlorhydrol/propylene glycol complex 59.3% byweight of the foregoing with respect to the finally complete weight ofthe contents of the container are introduced into the container atatmospheric pressure and at a temperature of 68 F. It should be observedat this point that 0.3% of the dichlorodifiuoromethane propellant whichis the highly volatile solvent subsequently will be lost duringevacuation for air purging so that the remaining amount of this ll willbe 59%.

The foregoing fill is left in the aerosol container for any desiredperiod of time which usually will be in the vicinity of one minute andwill be wholly determined by the speed of the filling, evacuation andcapping production line.

INext, a valved cap is loosely placed over the mouth of the containerwith the aforesaid concentrate therein.

The next step consists in applying a Ivacuum to the interior of thecontainer above the concentrate, the vacuum is at 15l of mercuryabsolute which will vaporize part of the dichlorodifluoromethanevolatile liquid and thereby purge the space over the concentrate toremove the air therefrom. The vacuum is applied for one second. Thecontainer has a capacity of cc.

While the container still is under vacuum, the cap is crimped. Machineswhich apply a vacuum to the interior of a container and subsequently,i.e., within about a second, crimp (seal) the valve cap to the containerwhile the container is still under a vacuum are well known and,therefore, will not be described in detail. By way of example, three (3)such machines are the Nalbach crimper, Model No. 8HVC made by NalbachEngineering Company; the Elgin filler, Model No. 6839 made by ElginEngineering Company; and, the Cozzolli filler, Model No. LF 1640 made byCozzolli Machine Company.

At this stage, there is still a substantial head space but the interiorof the can is at subatmospheric pressure and has been substantiallypurged of air and the head space is substantially filled with -vaporfrom the dichlorodifluoromethane.

Next, it is necessary to gas the container which constitutes theinsertion of the main body of a pressurized liquified gas propellant ina quantity sufficient to act as a propellant for the active ingredientsof the concentrate. The particular propellant employed in this exampleis dichlorodifluoromethane, although obviously other well knownpropellants will work equally well. 41% by weight of the said propellantis added to the can to make up 100.3% by weight of the concentrate pluspropellant, 0.3% of the dichlorodiiiuoromethane in the concentrate beinglost during the evacuation step immediately preceding crimping and, ofcourse, preceding the addition of the much larger amount of thedichlorodifiuoromethane that is added during the gassing step. The iinalhead space is 20% by volume.

EXAMPLE II Aerosol hair spray-In the iirst step, a concentrate is addedcomposed of the following constituents:

Percent by Weight Polyvinylpyrrolidone 2.50 Perfume 0.25 Ethanol(anhydrous) 92.75

Dichloroditluoromethane highly volatile liquid 4.50

54.30% by weight of this concentrate is charged into an aerosolcontainer open to the atmosphere. Subsequently, a valved cap is looselyemplaced and the interior of the container is subjected to a vacuum ofmercury absolute to remove air and vaporize part of the highly volatileliquid (an amount of about 0.3% of this liquid is Vaporized) to performthe air purging operation. The filling is done at atmospheric pressureand room temperature of 68 F. The evacuation proceeds for one 1) secondand then the cap is crimped in place (sealed) with l a hermetic sealaround the mouth of the container. The container has a capacity of 290cc. Finally, the now sealed container is gassed through the dischargeValve with 46% by weight of the main body of a liquied gas propellantconstituting 48% by weight of dichlorodiiiuoromethane and 52% by weightof dichloromonoiiuoromethane. The final head space is by volume.

EXAMPLE III Aerosol hair spray-This example differs from the precedingexamples by employing a superconcentrate plus a straight solvent illwherein the solvent contains the highly volatile liquid. Thesuperconcentrate is composed of the following:

Percent by weight Polyvinylpyrrolidone 12.50 Perfume 1.25 Ethanol(anhydrous) 86.25

10% by weight of the superconcentrate is charged into an open aerosolcontainer having a capacity of 290 cc. at a room temperature of 68 F.Concurrently therewith or subsequently thereto or prior thereto, theorder of the steps being inconsequential, there is charged into thecontainer a blend of organic solvent and highly volatile liquid composedas follows:

Percent by weight Ethanol (anhyrous) 95.50

Dichlorodiiluoromethane highly volatile liquid 4.50

The amount if this blend charged is 40.3% by weight, an amount of 0.3%of the highly volatile liquid evaporating during the subsequentevacuation.

Next a valved cap is loosely emplaced and the interior of the containeris subjected to a vacuum of 12" mercury absolute to remove air andvaporize part of the highly volatile liquid. While the interior of thecontainer still is under this vacuum, the cap is crimped to hermeticallyseal the container. 'Thereafter the container is gassed with 50% byweight of the main body of a liquified gas propellant composed of 48% byweight of dichlorodiuoromethane and 52% by weight oftrichloromonouoromethane. It will be found that vaporization of thehighly Volatile liquid purges the head space, prior to gassing ofsubstantially all of the air.

With respect to the foregoing three (3) examples, it is pointed out thatalthough water is not mentioned, it is present. For instance in ExampleI, the aluminum chlorhydrol/propylene glycol complex containsapproximately 5 to 10% by weight of water and in Examples II and III,the polyvinylpyrrolidone contains approximately 6% by weight of water.Also the anhydrous ethanol in Examples I through III, is never trulybone dry. It usually contains about 0.1% by weight of water. The finalhead space is 15% by volume.

EXAMPLE IV Aerosol-oil-in-water emulsion furniture polish-This examplediffers from the preceding three (3) examples (aside from its differencein active ingredients) principally in that there is used for the lill(exclusive of propellant) a mixture of water and concentrate solventwhich are mmiscible but which will form an emulsion. Into a 290 cc. opencontainer, there first are charged two I'ills. The fills may be chargedin succession, with either iirst, or concurrently. One lill is composedof 99% by weight of water and 1% by weight of polyoxyethylene sorbitanmonooleate making up 100%. 75% weight of this ll is charged into acontainer. The second till which is charged into the container is aconcentrate composed as follows:

Percent by Weight Isopar E 85.50 Dimethyl polysiloxane 10.00 Mineral oil1.00 Lemon oil 1.00

Dichloroditluoromethane highly volatile liquid 2.50

20.2% by weight of this lill is introduced into the can making a totalof 95.2% by weight. Isopar E is an organic solvent made by Humble Oiland Refining Company and having the following characteristics:

Aniline point-l65-l75 F. Aromatic content, weight percent-0.10 max.Specic gravity:

60/ 60 F.-0.7227 Distillatiom Initial B.P.--240 F. 50% B.P.-245-260 F.Dry point-290 F.

The container now has a 'valve cap loosely emplaced over the mouththereof, the container having been filled at atmospheric pressure androom temperature of 68 F. The space over the till is evacuated to 21"mercury absolute to remove air by purging and vaporization of part ofthe highly volatile liquid, then while still under vacuum the cap iscrimped to hermetically seal the same to the can. The container has acapacity of 290 cc.

The next steps are to agitate the container to form an emulsion and togas with liquid isobutane. These two steps are interchangeable in order.The amount of isobutane added is 5% by weight to make up 100% of thetotal iill. Approximately 0.2% of the highly volatile liquid is lostduring the evacuation operation, that is to say, about 2.3% of theoriginal 2.5% of said liquid, in the 20.2% by weight of the concentrateremains. The final head space is 25% by volume.

EXAMPLE V Aerosol water-in-oil furniture polish-First two liquid iillsare added at room, temperature and pressure. The order of the two fillsis of no consequence, either can be rst or both can be added together.IOne till is 100% l 1 water, 50% by weight of water is added. The secondiill is the concentrate which is composed as follows:

Percent by weight Mineral Spirits 150 83.70 Sorbitan oleate 3.50Glyceryl monooleate 1.80 Dimethyl polysiloxane 6.00 Soluble wax 3.00

Dichlorodifluoromethane/isobutane (90/10) highly volatile liquid 2.00

37.2 by weight of the second till is employed, the 0.2% being lost byevaporation during evacuation. The evaporation is principally of thehighly volatile liquid. It will be observed that the highly volatileliquid in this instance is 90% by weight of dichlorodiuoromethane and10% by weight of isobutane. Thereafter, the steps are substantially -asabove described which consists in loosely emplacing a valve cap, pullinga vacuum in the interior of the container of about 20 mercury absoluteto remove air and vaporize a part of the highly volatile liquid for thepurpose of purging the air. While still under vacuum the valve cap iscrimped to hermetically seal the can. Then the can is agitated andgassed in any order, the gas added is 100% dichlorodifluoromethane in anamount of 13% by weight thereof to make up the full 100% of the fill.The container has a capacity of 420 cc. The nal head space is 20% byvolume.

The Mineral Spirits 150 is an organic solvent made by Shell ChemicalCompany having the following characteristics:

Aniline point-151 F. Aromatic content, percent by volume-3 Specificgravity:

60/60" F.-0.777 Distillation:

Initial B.P.-323 F. 50% B.P.-342 F. Dry point-380 F.

EXAMPLE VI Aerosol water-in-oil furniture polish-The rst step is to llan aerosol container of 560 cc. capacity with 87.2% by lweight of aconcentrate composed as follow:

Percent by weight The ll is carried out at atmospheric pressure and roomtemperature of 68 F. as usual with the can open, then the can is looselycovered with a valve cap and a vacuum pulled to 20 of mercury absoluteto remove air and vaporize part of the highly volatile liquid. r[heamount of liquid volatilized is about 0.2% so that the concentrate llthus constitutes 87% by weight. With the vacuum maintained, the cap iscrimped to the container to hermetically seal it. Thereafter, thecontainer is gassed with 100% dichlorodiuoromethane in an amount of 13%by weight. The nal head space is 20% by volume.

In all of the foregoing examples, the gassing is performed after sealingthrough the discharge valve which is Opened for the purpose. However, ifdesired, in all of these examples the filling can be performed by thesocalled under-the-cap method followed by sealing of the valved cap tothe container which method is well known per se and a typical machinefor this purpose is the Kartridge Pak under-the-cap iiller, Model No.1951-9 made by the Kartridge Pak Company, For the purpose ofcompleteness, it is mentioned that a typical gasser that can be used forgassing through the opened discharge valve is a Keiffer gasser Model No.3-12, an alternate being Model No. 3-18. These are made by the KeiiferGas J et Company.

In all instances where no mention is made of the period for which thevacuum is pulled in the interior of the container to evaporate a part ofthe highly volatile liquid for air purging purposes, the time is onesecond.

In order to assist in understanding the invention, ow charts have beenprovided as part of this disclosure. These charts schematicallyillustrate the apparatus and steps involved.

Referring to FIG. l, the reference numeral 10 denotes a tank eitherexposed to the atmosphere or vented to the atmosphere or covered by alid not hermetically sealed thereto. In this tank 10, the concentrate ofany of the preceding examples is mixed or there is disposed any of thesundry lls. It will, of course, be understood that ingredients placed inthis tank will in each instance depend upon the desired formulation andthe invention is not to be limited to the specific examples above given.The reference numeral 12 denotes a supply tank in which there isdisposed a liquied gas which is highly volatile and which consists of atleast 90% of dichlo-rodiiluoromethane. A valve 14 yconnects the tank 12to a line 16 that runs through a valve 18 to the tank 10. Another valve20 in a line 22 connects the tank 10 to a gasser 24. When the valve 20is closed and the valve 18 is opened the highly volatile liquid will beintroduced into the mixing tank 10, this arrangement being utilized whenit is desired to add the highly volatile liquid directly to theconcentrate which concentrate also includes an organic solvent such asdescribed above wherein the highly volatile liquid is soluble. The rateof ow and duration of introduction of the highly volatile liquid intothe tank 10` is such as to obtain the desired (0.5% to 5.5% by weight ofthe organic solvent) concentration of the highly volatile liquid in theconcentrate which contains the organic solvent. A Valve 26 is disposedin a line running from the line 116 to a sparger 28. The sparger is in aline 29 running from the mixing tank 10 to a concentrate ller 30 whichmay be the Elgin or Cozzolli ller aforementioned. lf the highly volatileliquid is not introduced through the valve 18 into the mixing tank, saidliquid may be introduced in the desired proportions into the concentratethrough the sparger 28.

The concentrate ller 30 lls concentrate into open aerosol containers atroom temperature and pressure, the concentrate containing from 0.5% to5.5% by weight of the highly volatile liquid in the organic solvent withthe highly volatile liquid dissolved in said solvent.

From the concentrate filler 30 the open containers containing theconcentrate and highly volatile liquid are passed along a path 32 (alongwhich valved caps are loosely emplaced on the open mouths of thecontainers) to a vacuum crimper 34, e.g., the aforesaid Nalbach crimper.Here, a vacuum is drawn and held for 1/a to 11/2 seconds for eachcontainer and then the valve caps are then crimped (sealed) in place.When the caps are crimped in the crimper the aerosol containers willhave the concentrate and dissolved highly volatile solvent therein andat the same time the head space above the liquid in the can will beundef a vacuum. Then, the aerosol containers move along the path 36 t0the gasser 24 which may be the aforesaid Keiifer gasser. Here the mainbody of the liquified gas propellant is introduced. This may be the sameliquied gas as the highly volatile liquid in which event the gas isloaded from the tank 12 through the opened valves 14 and 20 and the line22. At this stage, i.e., after the gas till, the aerosol container isready for distribution.

It will be found that the head space in the containers has comparativelylittle air in it. Typically, there will be about 10% by volume of airleft in the head space which means that the amount of oxygen is about 2%by volume. Such containers are highly stable, have a long shelf life,have little corrosion and have little product deterioration. The amountof air can be reduced to as little as 0.5 by volume by pulling thelowest vacuum within the parameters as above set forth and pulling itfor the longest mentioned period of time. Also, the amount of airpresent will be reduced by adding up to by weight of one or more highlyvolatile liquids having a lower boiling point thandichlorodiuoromethane. It has been found that even up to a residue of byvolume of air in the head space using the purging system of the presentinvention produces a product which is considerably superior to those nowbeing marketed.

In FIG. 2 the reference numerals 10, 12, y14, 16, 18, 20, 22, 26, 28, 30and 32 denote components which are the same and are connected and areused in the same manner, as those detailed in FIG. 1. However, in FIG.2, the open containers leaving the filler 30 along the path 32 alongwhich valved caps are loosely lemplaced in the mouths of the containers,instead of being introduced into a vacuum crimper or sealer 34 andthereafter moved along a path 36 to a gasser 24, are led along the path32 to an underthe-cap filler 38, in which the containers are gassed fromthe tank 12 with a main body of liquied gas propellant from the tank 12and then sealed to the valved caps.

In FIG. 3 a mixing tank A40 is provided in which a superconcentrate ismixed, said tank being at atmospheric pressure. The reference numeral 42denotes a supply tank for the highly volatile liquid and the referencenumeral 44 a storage tank for an organic solvent such as anhydrousethanol. A valve 46 connects the tank 42 to a line 48 that has a branchline 50` including a valve 52. A valve 54 also connects the tank 44 tothe line 50. A valve 56 connects the line 48 to a sparger 58 and a valve60 connects the line 48 to a through-the-valve gasser (not shown) or toan under-the-cap ller 62. The active ingredients are blended in themixing tank 40 with the organic solvent fed from the tank 44 and, ifdesired, with the desired amount, within the range previously indicated,of the highly volatile liquid so as to have present from about 0.5 toabout 5.5% of said liquid by weight of the total amount of the organicSolv-ent included in a filled container. The ingredients of thesuperconcentrate are so proportioned that said superconcentrate can beblended with an additional amount of organic solvent to form aconcentrate composed of up to 50% by weight of the superconcentrate. Thesuperconcentrate is fed along a line 64 from the mixing tank to a filler=66 which introduces the proper amount of superconcentrate to openaerosol containers. The containers (still open) are led along a path 68to a second filler 70 `where organic solvent from the tank 44 is fedthrough a line 72 to make up the balance of the solvent needed toincorporate a correct proportion of the solvent in the concentrate. Nowthe containers in which a proper amount of concentrate plus dissolvedhighly volatile liquid is disposed are led along a path 74 during whichvalved caps are loosely emplaced over the open mouths of the containers.The path 74 feeds the containers to the under-the-cap filler 62, whichevacuates the containers to the proper indicated degree, then fills thecontainers with the main body of liquilied gas propellant and crimps thecaps to the containers to provide nished aerosol containers. Alternatelythe path 74 feeds the containers to a vacuum crimper, such as thecrimper 34, which rst evacuates the containers to the proper degree andthen crimps the caps to the containers. The sealed, evacuated containersthen are led to a gasser (not shown) such as the gaser 24, whichintroduces the main body of liquied gas propellant through the containerdispensing valves which are held open for this purpose.

It thus will be seen that there are provided systems which achieve theseveral objects of the present invenuon and which are well adapted tomeet the conditions of practical use.

As various possible embodiments might be made of the above invention andas various changes might be made in the embodiments above set forth, itis to be understood that all matter herein described or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

Having thus described the present invention, there is claimed as new anddesired to be secured by Letters Patent:

1. In a method for lling an aerosol type container, constituting acontainer having a valved cap hermetically sealed to the containermouth, and in which container are disposed a concentrate composed of atleast one active ingredient and an organic solvent and also a liquiiiedgas propellant: that improvement including incorporating into theconcentrate a nontoxic, nonilammable, stable, highly volatile liquidhaving a boiling point of from about -l0 F. to about 45 F., which isinert to the concentrate and propellant and which is present in anamount of from about 0.5% to about 5.5% by weight of the organicsolvent, said highly volatile liquid including at least by weight ofdichlorodiuoromethane and from l0% to about 10% by weight of otherhighly volatile liquids, the total vapor pressure of the blend oforganic solvent and highly volatile liquid being between about 5p.s.i.a. and about 12 p.s.i.a., introducing the concentrate, includingthe highly volatile liquid, into a container open to the atmosphere,then evacuating the space in the container above the concentrate andhighly volatile liquid to a vacuum of between about 3 p.s.i.a. and about12 p.s.i.a. for about Mi second to about 11/2 seconds so as to purgemost of the air above the concentrate with the vapor from the highlyvolatile liquid, said vacuum being between about the vapor pressure ofthe blend and about 3 p.s.i.a. below the vapor pressure of the blend,and, subsequently, hermetically sealing a valved cap to the mouth of thecontainer and introducing the main body of the propellant into thecontainer.

2. A method as set forth in claim 1 wherein the other highly volatileliquids in the 0% to about 10% by weight of the highly volatile liquidare selected from the class consisting of dichlorotetrailuoroethane,diuoromonochloromethane, n-butane, isobutane and propane.

3, A method as set forth in claim 1 wherein the organic solvent isselected from the class consisting of alcohols, aliphatic petroleumderivatives, mineral spirits, aromatic petroleum derivatives, esters,mineral oils, glycol ethers, ketones, chlorinated solvents andturpentine.

4. A method as set forth in claim 1 wherein the container is filled withthe concentrate including the highly volatile liquid, so as to leave ahead space volume of about 1A; to about Vs.

5. A method as set forth in claim 1 wherein the final head space volumeof the sealed, gassed container is about 10% to about 30% of the volumeof the container.

6. A method as set forth in claim 1 wherein the residual air containedin the final head space of the sealed, gassed container is from about0.5 by volume to about 15% by volume.

7. A method as set forth in claim 1 wherein the residual air containedin the iinal head space of the sealed, gassed container is from about0.5 by volume to about 10% by volume.

8. A method as set forth in claim 1 wherein the period of evacuation isabout one (1) second.

References Cited UNITED STATES PATENTS 3,224,158 12/1965 Baumann 53-223,336,720 8/1967 Honish 53--22 TRAVIS S. McGEHEE, Primary Examiner U.S.Cl. X.R. 53-36

